Screen motion wallpaper app keeps saying "allow screen motion access your photos in setting.app"

Is your iPod jailbroken?

Yes if you want screen motion in your background?

What you will be wanting to do is completely delete the app and re-download it, it will then give you the option to allow access to camera roll when you click a wallpaper to download. Hope all this makes sense most important part is the removal and re-install of the app.